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Allergies rise with spring in the air

July 10th, 2008

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Allergies rise with spring in the air

Warmer weather signals the start of suffering for one in four Canadians

Tennyson's young man likely did not suffer from airborne allergies. While the warm spring air is enough to lure most of us from our winter cocoons, it signals the beginning of allergy season for the one in four Canadians allergic to tree and grass pollens, spores, moulds, fungi or other airborne particles such as dust mites and pet dander.

When spring winds begin to blow, they carry these allergens with them, provoking not spring fever but so-called hay fever in susceptible souls. The result? A menu of cold-like symptoms that leave allergy sufferers itching -- literally -- for the next hard frost.

Hay fever sufferers are likely to be distracted from thoughts of love by their repeated and prolonged sneezing attacks; watery, stuffy noses; red and swollen eyes; breathing difficulties; and itching of the nose, eyes, throat, mouth or ears. Longer-term effects include chronic sinusitis (the inflammation of the sinus cavities), headaches, ear problems, sleep disturbance or even asthma.

Tree pollens are at their peak in spring and early summer. Ragweed pollen is in the air in the fall. And for those allergic to dust mites, mould or pet dander, allergy "season" can be a year-round affair.

"Asthma and allergies are the single biggest reason for school absences in the country," says Bill VanGorder, vice-president of asthma and allergies with the Canadian Lung Association and chief executive of the Lung Association of Nova Scotia. "And that would suggest to us that it's a very high cause of workplace absences, too."

Dr. Redwan Moqbel, a professor in the University of Alberta's department of medicine, has been studying asthma, allergies and immunobiology for nearly three decades. He describes allergic reactions as the body's "spurious response" to what it perceives as invaders.

Dr. Moqbel says when airborne allergens such as pollen enter the body, through the mouth, eyes, lungs or skin, they set off a rapid chain reaction "in previously sensitized subjects."

Allergens trigger an antibody called immunoglobulin E -- IgE for short -- which binds to the surface of inflammatory cells called mast cells. Mast cells in turn release histamine and other biochemical agents that have what Dr. Moqbel terms "spasmogenic and pro-inflammatory effects." In other words, they cause changes in the smooth muscles of the airways and gut, as well as sneezing, itching, swelling, watery eyes, mucous production and congestion.

One research hypothesis suggests allergies may be an evolutionary throwback to a time when parasitic worms plagued our ancestors, Dr. Moqbel says.

"It's fascinating. In the past, the immune system needed IgE and mast and other cells to fight these parasites. Now that we no longer have parasites, the parasite-fighting system still wants a target. And the target is our own tissue in the form of an allergic reaction."

The key to allergies is IgE, Dr. Moqbel says. "If you don't have this antibody, it's unlikely you are allergic." Scientists are researching drug therapies that could potentially prevent IgE release and stop the allergic response before it starts.

"Most people tough it out, and that's too bad when we can do something about allergies," VanGorder says.

Hay fever sufferers should pay attention to pollen and stay indoors with windows closed and the air conditioning on when counts are high. Antihistamines, prescription nose sprays that contain steroids, and eye drops with antihistamines and decongestant may help, as can nose sprays and drops that contain cromoglycate, an anti-allergic agent with some anti-inflammatory effects. Severe symptoms may be eased with the steroid prednisone. Allergy shots are another option.